The present invention relates to an image reading apparatus, and relates in particular to an EMI (Electro Magnetic Interference) countermeasure therefor.
Image reading apparatuses, such as image scanners and facsimile machines, are well known as digital image input apparatuses that for use are now closely associated with computers. Concurrently, as the development of the computers with which they are now generally employed has continued, the reading speeds attained by these image reading apparatuses have been increased, year after year.
As is shown in FIG. 4, for a conventional flatbed image scanner, a CCD 22, an A/D converter 25 and a buffer 28 are provided for a carriage 20, and an image processing ASIC 52, which incorporates a controller 51 for generating control signals for the CCD 22 and the A/D converter 25, is provided for a main substrate 41 that is fixed to a case 11. The image processing ASIC 52 is connected to the CCD 22, the A/D converter 25 and the buffer 28 by a flexible flat cable (hereinafter referred to as an FFC) several tens of centimeters in length. Since for this conventional flatbed scanner configuration the path provided by the FFC for the transmission of digital image data signals is very long, it is an acknowledged fact that appropriate EMI (ElectroMagnetic Interference) countermeasures are required for the FFC.
However, to reduce the EMI that accompanies the transmission of digital image data along the FFC, EMI countermeasures must be taken for the individual FFC data lines by providing a resistor for each of them, and this provision of EMI countermeasures would increase the overall unit cost.